The invention relates to upgrading carbonaceous materials such as tar sands. In one aspect, tar sands are upgraded in a solvent extraction process. In another aspect, an apparatus is provided for extracting tar sands.
Tar sands are chiefly particles of silica having a coating of carbonaceous material in the form of a heavy oil. Tar sands frequently contain in excess of 10 percent by weight of carbonaceous material which can be recovered and upgraded to form alternate petroleum products. For prime tar sands, recoveries of nonconventional oil in the range of 10-20 gallons per ton of tar sand should be achievable.
Because large quantities of tar sand are recoverable by conventional mining techniques, processes for separating the tar from the sand are of high interest. Processes which obviate materials handling problems are also highly desirable.